G1 GC for 100GB+ heaps

[Tao Mao]

I had experience in tuning G1 with ~30GB in production environment (not as
large as you attempt :). I found it helpful to play around the following
JVM options as well as Java monitoring tools such as Jconsole/JMC:

-Xmx<nG> -Xms<nG>
-XX:MaxGCPauseMillis=<ms>
-XX:InitiatingHeapOccupancyPercent=<%>
-XX:+PrintReferenceGC
-XX:+ParallelRefProcEnabled
-XX:+PrintAdaptiveSizePolicy
-XX:ParallelGCThreads=n
-XX:ConcGCThreads=n
-XX:G1MixedGCCountTarget=n

As for region sizing, since you have a large heap, you may want to check
the relationship of region sizes and humongous object allocation, making
sure they are harmonious. If you suspect any problem in that end, you can
try G1PrintHeapRegions to diagnose.

Hope this helps.

changed cc to hotspot-gc-use

Thanks.
Tao Mao



On Wed, Jul 22, 2015 at 6:51 AM, Kees Jan Koster <kjkoster at java-monitor.com>
wrote:

> Dear All,
>
> Marcus Lagergren suggested I post these questions on this list. We are
> considering switching to using the G1 GC for a decently sized HBase
> cluster, and ran into some questions. Hope you can help me our, or point me
> to the place where I should ask.
>
> First -> sizing: Our machines have 128GB of RAM. We run on the bare metal.
> Is there a practical limit to the heap size we should allocate to the JVM
> when using the G1 GC? What kind of region sizing should we use, or should
> we just let G1 do what it does?
>
> Second -> failure modes. Does G1 have any failure or fall-back modes that
> it will use for edge cases? How do we monitor for those?
>
> Finally: Are there any gotcha’s to keep in mind, or any tunables that we
> have to invest time into when we want to run smoothly with 100GB+ heap
> sizes?
>
>
> --
> Kees Jan
>
> http://java-monitor.com/
> kjkoster at kjkoster.org
> +31651838192
>
> Change is good. Granted, it is good in retrospect, but change is good.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-gc-use/attachments/20150722/184c8859/attachment.html>